jer301

I really have not had as much trouble with the Kumhos as i did the dunlops. I did have an alignment done when i got them. i still run 45-49psi on the track, but most of the turns are off camber. I was talking to one of the EVO X drivers and he has the same issue with his front tires. He has to keep his pressures up to survive the turns. we suspect it is the mcphearson strut front suspension, but, we are not in agreement on how much positive camber that the suspension gives to the outside tire through a turn. I say no more than a degree and he believes it to be about 2 degrees or more. They are two different cars though.

ambystom01

iTrader: (7)

That still sounds like a ridiculous tire pressure. I run maybe 38 PSI and I'll likely drop it down another PSI or two.

jer301

I usually drop mine about 2 or 3 psi during the event. You have mentioned tracks in some of your posts. do you road race or autox? Just curious b/c i have gotten very different opinions on this subject from road race drivers and autox'rs. here is a short video of our course. Again only autox'rs put their tire pressures that high but the corners are very tight on autox tracks.

http://www.youtube.com/watch?v=DgDPvKsw_Gc

We may be argueing apples and oranges here but i have only been autoxing for about a year, so if you ahve any advice i will gladly take it.

ambystom01

iTrader: (7)

Road race which explains the difference.

DJ Brett B

iTrader: (12)

To the OP;
I'm not familiar with the General tire mentioned but anything with that tread rating will obviously out-last the XS and since you are stressing the cost factor I would assume you would want more time and life out of your tires before having to spend the money to replace them again, and if you dont autocross or do HPDE frequently I'm sure they will be great overall-

not trying to threadjack, just interested in what differences you noticed since I run RE-01, which you prefer?

I agree that tire pressure is very high- seems like running ~38psi when the tire is hot is ideal for most street tires, anything much higher than 40psi feels really bouncy on my RE-01's... I ran about 32psi at Miller track because they would heat up to 38, for street driving close to 38 seems perfect

jer301

Road race sounds like a lot of fun too. I am going to an event in Louisiana next month but i won't be driving the lancer. I will be driving a 1650lb Porsche 914 with 200whp. The guy that owns it does both. He does not pump his tire pressures up during autox, but he is on 315 Hoosiers. Can't wait. Any advice for an autox'r who is going to cut his teeth on a road course?

ambystom01

iTrader: (7)

For overall dry grip, the Kumhos are king but in the wet, they're not even close to the RE01Rs. Even in street driving, the difference in easily noticeable. I also preferred the turn in of the RE01Rs, the Kumhos are bit less confidence inspiring and communicative.

ambystom01

iTrader: (7)

Add smoothness, the key to road racing is smoothness, not speed or power.

DJ Brett B

iTrader: (12)

have them show you "the line" meaning by using the whole track and driving smooth, you will carry much more speed- ride around the course at least a few times before driving it to get a feel for it, the braking zones, where to begin turning in to corners, where to let the car drift out to (not literally drift as in drifting) coming out of corners, come onto throttle as you open the steering wheel up coming out of corners (rather than punching the throttle with the wheel turned), look way far ahead of you into the corner as far as you can see to see where it goes rather than looking right in front of you, etc. Those are the beginning things I was told which really helped me to understand the rhythm of the track and make me faster/better...and most importantly have fun!

DJ Brett B

iTrader: (12)

Awesome thats helpful, thanks Amby!

jer301

Think we kinda agreed that the high tire pressure is just for autox. the tire temps, inside, middle, and outside seem more even at these pressures during an autox event. i pump them up to 49 for the stock dunlops (45 for the kumhos) and reduce pressure to find the tires sweet spot so to speak. this came from the following link which is considered the bible of autox racing:

http://farnorthracing.com/autocross_secrets4.html

i have set the link to the section about tires. agian autox is very tight turns at about 30 - 40 mph. i only discuss the autox point of view b/c some of these guys have posted pics of tires and what traditionally happens to autox tires on a course. there is a tire wear thread with a pic from I am god. this is very common in autox for drivers with low tire pressure an STOCK suspension. Negative camber usually minimizes it but in autox it takes you out of stock class.

jer301

Look ahead is definately one of the first rules of autox. I usually have a blast. I did finally learn from a couple of drivers later that day how to brake at just the right moment get the back end loose in turns and shaved almost a second off my time in the video. people think i am crazy but i walk the course at least six times. i did try to push the car through a couple of turns in that video. I need to work on unwinding in a turn to regrip the car. thank you for the advice.

DJ Brett B

iTrader: (12)

no problem, in fact one of my instructors told me thats really a common thing auto-x drivers do, if you accelerate to early/quickly out of the corner you can feel the tires scrubbing

thielepr

At 18 seconds on your video you lost about 1/3 of your front tire. I have run some track days in a kart track and the car needs a LSD.

jer301

Yea that was pretty bad. along with the road noise you can feel when you are pushing to hard and the car is understeering through a turn. what i am supposed to do Brake really hard just before the turn to transfer weight to the front tires turn into the turn and unwind the the steering wheel a little bit and bring it back. this allows the car to regrip. Another trick I learned from a driver with the same type of car (FWD, no LSD) was to left foot brake through a turn. with the right tire pressure setup 49F/42R, if you do this and tap the brake up to the apex, the rear end will rotate and you are able to oversteer slightly through the turn. You can go much faster without killing the tires or fighting understeer. As for the LSD stock class does not permit it but plenty of drivers follow these methods and do not shred their tires.